fix(soroban): handle DynamicBytes in ABI spec, codec, and LLVM type system

[aryanbaranwal001]

Description

Any solidity contract on soroban using bytes as a function parameter or return type would panic at compile time. This was caused by three independent gaps in the DynamicBytes emit path.

The following contract now compiles to a valid WASM binary:

// SPDX-License-Identifier: Apache-2.0
contract BytesWriteStub {
    bytes public data;

    function set_data(bytes memory d) public {
        data = d;
    }
}

Key Changes

• codegen/encoding/soroban_encoding.rs : added DynamicBytes arm to soroban_decode_arg and soroban_encode_arg, same as String and Address.

• emit/soroban/mod.rs: added DynamicBytes arm to emit_function_spec_entry for both inputs and outputs.

• emit/binary.rs: extended the Soroban guard in var_ty_uses_pointer_storage() to cover DynamicBytes, on soroban bytes is i64 handle, not a ptr, so its LLVM alloca must be i64 not ptr

Tests

• Added one test in soroban_testcases/dynamic_bytes.rs: covering set_data call with empty bytes then with b"hello", reads back via the auto generated data() getter, and asserts equality. Verifying all three fixed gaps.